Chronic Obstructive Pulmonary Disease: Effects beyond the Lungs

Chronic obstructive pulmonary disease (COPD) is a growing global epidemic that is particularly important in developing countries. Morbidity and mortality from COPD will rise as populations age and mortality from cardiovascular and infectious diseases falls. Whereas cigarette smoking is the commonest cause of COPD in developed countries, COPD is also seen in nonsmokers, particularly in developing countries, yet very little is know about this form of COPD. COPD is primarily characterized by the presence of airflow limitation resulting from inflammation and remodelling of small airways and is often associated with lung parenchymal destruction or emphysema. It is increasingly recognised that COPD extends beyond the lung and that many patients have several systemic manifestations that can further impair functional capacity and health-related quality of life In addition, COPD is associated with several other diseases, such as cardiovascular diseases, osteoporosis, diabetes, and metabolic syndrome, more commonly than expected by chance. These associations are greater than expected from common aetiological factors, such as smoking, suggesting that these comorbidities may be causally associated with the mechanisms of COPD. Systemic effects and comorbidities of COPD increase both the risks of hospitalisation and mortality and the costs, and are therefore a topic of increasing concern Indeed, cardiovascular disease and lung cancer are the commonest causes of death in patients with COPD Although comorbidities are more commonly seen in association with severe COPD, they may also be associated with milder or earlier disease.